• a light strong grey lustrous corrosion-resistant metallic element used in strong lightweight alloys (as for airplane parts); the main sources are rutile and ilmenite
Example sentence
• Many aircraft and spacecraft use titanium for its durability.
• a solid silvery grey radioactive transuranic element whose atoms can be split when bombarded with neutrons; found in minute quantities in uranium ores but is usually synthesized in nuclear reactors; 13 isotopes are known with the most important being plutonium 239
Example sentence
• The United States has stockpiled tons of plutonium.
• a brittle silver-white metalloid element that is related to selenium and sulfur; it is used in alloys and as a semiconductor; occurs mainly as tellurides in ores of copper and nickel and silver and gold
Example sentence
• The melting point of tellurium is approximately 449.5 degrees Celsius.
• (microbiology) single-celled or noncellular spherical or spiral or rod-shaped organisms lacking chlorophyll that reproduce by fission; important as pathogens and for biochemical properties; taxonomy is difficult; often considered to be plants
Example sentence
• A single bacterium can multiply into millions within a few hours.
• a lustrous grey strong metallic element resembling titanium; it is used in nuclear reactors as a neutron absorber; it occurs in baddeleyite but is obtained chiefly from zircon
Example sentence
• The zirconium oxide coating on the surface of certain metals provides excellent protection against corrosion.
• a light soft silver-white metallic element of the alkali metal group; oxidizes rapidly in air and reacts violently with water; is abundant in nature in combined forms occurring in sea water and in carnallite and kainite and sylvite
• a toxic nonmetallic element related to sulfur and tellurium; occurs in several allotropic forms; a stable grey metallike allotrope conducts electricity better in the light than in the dark and is used in photocells; occurs in sulfide ores (as pyrite)
Example sentence
• The nutritional intake of selenium is important for human health.
• a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals
Example sentence
• Milk and dairy products are excellent sources of calcium.
• a very light colorless element that is one of the six inert gasses; the most difficult gas to liquefy; occurs in economically extractable amounts in certain natural gases (as those found in Texas and Kansas)
Example sentence
• The balloon floated in the air due to the presence of helium.
• a grey tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons
Example sentence
• The name hafnium derives from Hafnia, the Latin name for Copenhagen.
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